Go here to install the most recent version of Toribash: http://www.toribash.com/downloads.php (version 5.12) I recommend using Steam instead, as Steam will automatically keep your game up-to-date. Here's the link to Toribash in the Steam Store: http://store.steampowered.com/app/248570/Toribash/
If you want to copy over replays, mods and screenshots, I'd recommend you to download and install the newest version of Toribash first, then go into your old Toribash version's folders and copy all the stuff you want to keep, like replays, screenshots, whatever, over to the new folder (duplicates will automatically be detected, select the option that tells you to skip duplicates when it pops up)
To uninstall the older version of Toribash, check out these instructions: http://www.wikihow.com/Uninstall-Pro...80.9D_Menu_sub Use method 3 to uninstall the oldest version of Toribash.
Also, it's totally okay to ask as many questions as you'd like. Don't worry.